One example of switching regulators with high efficiency under a light load is a switching regulator proposed in Patent Document 1.
The switching regulator proposed in Patent Document 1 stops switching control under a light load and holds an upper switching element and a lower switching element in an off state. Stopping switching control eliminates switching loss, and thus the switching regulator proposed in Patent Document 1 offers high efficiency under a light load.
When the switching regulator proposed in Patent Document 1 finds an output voltage to have lowered while not performing switching control, it restarts switching control. After switching control is restarted, the switching regulator proposed in Patent Document 1 stops switching control again if the load is light, and continues switching control if the load is heavy.